1. Field of Invention
The present invention relates to a method for adjusting a shooting condition of a digital image, and more particularly to a method for adjusting a shooting condition through motion detection.
2. Related Art
Along with the rapid development of the digital camera, most people like to record a memorable moment through photographing. However, when a traditional camera utilizing films or a digital camera is used to take photographs, some blurred images may be generated due to the user's unstable holding of the camera. Since the camera is held by hand, the hand shake problem cannot be avoided. The difference of the holding stability of different person causes the involuntary displacement at the instant when the shutter is pressed. In order to avoid the blurred image caused by the hand shake, the manufacturer of the digital camera corrects the blurred image in a manner of hardware or software.
Different digital camera manufacturers employ different anti-shake mechanisms. The commonly known anti-shake methods usually include increasing the photosensitivity (ISO), increasing the shutter speed, or increasing the aperture values. The aforementioned various methods are all used to reduce the shutter speed, thereby reducing the influence of the hand shake on the digital image. However, the aforementioned methods all have some defects. In view of the adjusting manner and hardware cost, the method of adjusting the photosensitivity is cheaper than the other methods. However, increasing the photosensitivity may cause a larger noise, which reduces the imaging quality of the digital image. Adjusting the shutter speed and the aperture value may reduce the light receiving amount of the photosensitive element, thereby affecting the imaging luminance of the digital image.
Besides, the clearness of the digital image is also affected by the movement of the shot object. During the sloshing of the shot object, if the shooting is done under a low shutter speed, the obtained digital images may also be blurred. Thus, someone has proposed that the shake of the digital camera and the sloshing of the shot object can be respectively detected, and the shooting condition of the digital image is compensated according to the movement vectors of the shake of the digital camera and the sloshing of the shot object, thereby minimizing the influence of the factors on shooting.
In the prior art, several consecutive images are captured, and the analysis on the camera shake and the sloshing of the shot object is conducted according to the displacement of each pixel in the consecutive images. Referring to FIG. 1, a schematic view of a pixel calculation for a digital image according to the prior art is shown. The upper left side and upper right side of FIG. 1 show two consecutive digital images 111 and 112. By analyzing each pixel, the movement change of the camera and the shot object can be effectively found out (assuming that the shot object is a face in FIG. 1). In other words, the movement change is indicated by the arrows at the lower part of FIG. 1. However, being limited by the inherent calculation capability, the digital camera with a common performance cannot accomplish calculating all the pixels in the digital image.